Wouldn it make better sense to wait for the new type of ELTs that are coming in a few years?
While a new type of improved ELTs is becoming available, they currently cost $1,500 to $2,000 or more. It will certainly be several years before they are anywhere near as affordable as a $219 ACK Technologies unit is today. Spend 200 bucks, use it for five years, and replace it with a something better when it becomes affordable. The cost of this approach is only $40 per year. On the other hand, doing nothing about a serious problem because we are waiting for something better is not a responsible position.